FAILED: patch "[PATCH] cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER" failed to apply to 6.12-stable tree

FAILED: patch "[PATCH] cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER" failed to apply to 6.12-stable tree

[gregkh]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 29458e62d0829cbc99435f3e44fd560f9bbf1da7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090316-sincere-breeding-8254@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 29458e62d0829cbc99435f3e44fd560f9bbf1da7 Mon Sep 17 00:00:00 2001
From: Terry Bowman <terry.bowman@amd.com>
Date: Mon, 3 Aug 2026 17:17:57 -0500
Subject: [PATCH] cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER
 register read

cxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from
the RCRB MMIO block using a readl() loop bounded by sizeof(struct
aer_capability_regs). This struct is a software layout and its embedded
struct pcie_tlp_log is larger than the on-wire AER capability. As a
result the loop reads past the mapped AER register block.

The over-read also populates the software-only tail fields including
header_log.header_len. An out-of-range header_len passed to
pcie_print_tlp_log() can then loop past the header log buffer and cause
a second out-of-bounds read.

The read was correct when introduced, but struct pcie_tlp_log has since
grown (Header Log and TLP Prefix Log sizes, header_len and flit fields),
so sizeof(struct aer_capability_regs) no longer matches the physical AER
capability.

Bound the read to the physical AER registers, header through the 16 byte
Header Log. Zero the destination first so the software-only fields are
deterministic.

Fixes: 6ac07883dbb5 ("cxl/pci: Add RCH downstream port error logging")
Reported-by: Sashiko <sashiko@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20260803221810.3685703-2-terry.bowman@amd.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
index 0a8b3b9b6388..8a3965edaa12 100644
--- a/drivers/cxl/core/ras_rch.c
+++ b/drivers/cxl/core/ras_rch.c
@@ -58,13 +58,28 @@ void cxl_disable_rch_root_ints(struct cxl_dport *dport)
 static bool cxl_rch_get_aer_info(void __iomem *aer_base,
 				 struct aer_capability_regs *aer_regs)
 {
-	int read_cnt = sizeof(struct aer_capability_regs) / sizeof(u32);
+	/*
+	 * Bound the copy to the physically-defined AER registers (header
+	 * through the 16-byte Header Log). struct aer_capability_regs is a
+	 * software layout whose embedded struct pcie_tlp_log is larger than
+	 * the on-wire AER capability; copying sizeof(*aer_regs) would
+	 * over-read the RCRB-mapped MMIO block.
+	 */
+	int read_cnt = (PCI_ERR_HEADER_LOG + 16) / sizeof(u32);
 	u32 *aer_regs_buf = (u32 *)aer_regs;
 	int n;
 
 	if (!aer_base)
 		return false;
 
+	/*
+	 * Zero the destination so the software-only tail fields
+	 * (e.g. header_log.header_len) are deterministic rather than
+	 * left as uninitialized stack, which could drive a bogus loop
+	 * length in pcie_print_tlp_log().
+	 */
+	memset(aer_regs, 0, sizeof(*aer_regs));
+
 	/* Use readl() to guarantee 32-bit accesses */
 	for (n = 0; n < read_cnt; n++)
 		aer_regs_buf[n] = readl(aer_base + n * sizeof(u32));

[PATCH 6.12.y 1/4] cxl/pci: Remove unnecessary CXL Endpoint handling helper functions

[Sasha Levin]

From: Terry Bowman <terry.bowman@amd.com>

[ Upstream commit ca3d1a53e62093d17436abd447463da9c0f4e56b ]

The CXL driver's cxl_handle_endpoint_cor_ras()/cxl_handle_endpoint_ras()
are unnecessary helper functions used only for Endpoints. Remove these
functions as they are not common for all CXL devices and do not provide
value for EP handling.

Rename __cxl_handle_ras to cxl_handle_ras() and __cxl_handle_cor_ras()
to cxl_handle_cor_ras().

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://patch.msgid.link/20260114182055.46029-5-terry.bowman@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Stable-dep-of: 29458e62d082 ("cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cxl/core/pci.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 5b46bc46aaa95..c70b75a6f6fe5 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -650,8 +650,8 @@ void read_cdat_data(struct cxl_port *port)
 }
 EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
 
-static void __cxl_handle_cor_ras(struct cxl_dev_state *cxlds,
-				 void __iomem *ras_base)
+static void cxl_handle_cor_ras(struct cxl_dev_state *cxlds,
+			       void __iomem *ras_base)
 {
 	void __iomem *addr;
 	u32 status;
@@ -667,11 +667,6 @@ static void __cxl_handle_cor_ras(struct cxl_dev_state *cxlds,
 	}
 }
 
-static void cxl_handle_endpoint_cor_ras(struct cxl_dev_state *cxlds)
-{
-	return __cxl_handle_cor_ras(cxlds, cxlds->regs.ras);
-}
-
 /* CXL spec rev3.0 8.2.4.16.1 */
 static void header_log_copy(void __iomem *ras_base, u32 *log)
 {
@@ -693,8 +688,8 @@ static void header_log_copy(void __iomem *ras_base, u32 *log)
  * Log the state of the RAS status registers and prepare them to log the
  * next error status. Return 1 if reset needed.
  */
-static bool __cxl_handle_ras(struct cxl_dev_state *cxlds,
-				  void __iomem *ras_base)
+static bool cxl_handle_ras(struct cxl_dev_state *cxlds,
+			   void __iomem *ras_base)
 {
 	u32 hl[CXL_HEADERLOG_SIZE_U32];
 	void __iomem *addr;
@@ -727,11 +722,6 @@ static bool __cxl_handle_ras(struct cxl_dev_state *cxlds,
 	return true;
 }
 
-static bool cxl_handle_endpoint_ras(struct cxl_dev_state *cxlds)
-{
-	return __cxl_handle_ras(cxlds, cxlds->regs.ras);
-}
-
 #ifdef CONFIG_PCIEAER_CXL
 
 static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
@@ -810,13 +800,13 @@ EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, CXL);
 static void cxl_handle_rdport_cor_ras(struct cxl_dev_state *cxlds,
 					  struct cxl_dport *dport)
 {
-	return __cxl_handle_cor_ras(cxlds, dport->regs.ras);
+	return cxl_handle_cor_ras(cxlds, dport->regs.ras);
 }
 
 static bool cxl_handle_rdport_ras(struct cxl_dev_state *cxlds,
 				       struct cxl_dport *dport)
 {
-	return __cxl_handle_ras(cxlds, dport->regs.ras);
+	return cxl_handle_ras(cxlds, dport->regs.ras);
 }
 
 /*
@@ -913,7 +903,7 @@ void cxl_cor_error_detected(struct pci_dev *pdev)
 		if (cxlds->rcd)
 			cxl_handle_rdport_errors(cxlds);
 
-		cxl_handle_endpoint_cor_ras(cxlds);
+		cxl_handle_cor_ras(cxlds, cxlds->regs.ras);
 	}
 }
 EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
@@ -942,7 +932,7 @@ pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
 		 * chance the situation is recoverable dump the status of the RAS
 		 * capability registers and bounce the active state of the memdev.
 		 */
-		ue = cxl_handle_endpoint_ras(cxlds);
+		ue = cxl_handle_ras(cxlds, cxlds->regs.ras);
 	}
 
 
-- 
2.53.0

[PATCH 6.12.y 2/4] cxl/pci: Remove unnecessary CXL RCH handling helper functions

[Sasha Levin]

From: Terry Bowman <terry.bowman@amd.com>

[ Upstream commit eb78ef4d6f0e51243c1ee117f801dbc503e886ab ]

cxl_handle_rdport_cor_ras() and cxl_handle_rdport_ras() are specific
to Restricted CXL Host (RCH) handling. Improve readability and
maintainability by replacing these and instead using the common
cxl_handle_cor_ras() and cxl_handle_ras() functions.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Alejandro Lucero <alucerop@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://patch.msgid.link/20260114182055.46029-6-terry.bowman@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Stable-dep-of: 29458e62d082 ("cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cxl/core/pci.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index c70b75a6f6fe5..42fc18878b0d6 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -797,18 +797,6 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, CXL);
 
-static void cxl_handle_rdport_cor_ras(struct cxl_dev_state *cxlds,
-					  struct cxl_dport *dport)
-{
-	return cxl_handle_cor_ras(cxlds, dport->regs.ras);
-}
-
-static bool cxl_handle_rdport_ras(struct cxl_dev_state *cxlds,
-				       struct cxl_dport *dport)
-{
-	return cxl_handle_ras(cxlds, dport->regs.ras);
-}
-
 /*
  * Copy the AER capability registers using 32 bit read accesses.
  * This is necessary because RCRB AER capability is MMIO mapped. Clear the
@@ -878,9 +866,9 @@ static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
 	pci_print_aer(pdev, severity, &aer_regs);
 
 	if (severity == AER_CORRECTABLE)
-		cxl_handle_rdport_cor_ras(cxlds, dport);
+		cxl_handle_cor_ras(cxlds, dport->regs.ras);
 	else
-		cxl_handle_rdport_ras(cxlds, dport);
+		cxl_handle_ras(cxlds, dport->regs.ras);
 }
 
 #else
-- 
2.53.0

[PATCH 6.12.y 3/4] cxl/pci: Remove CXL VH handling in CONFIG_PCIEAER_CXL conditional blocks from core/pci.c

[Sasha Levin]

From: Dave Jiang <dave.jiang@intel.com>

[ Upstream commit 7ff8b1d60881c5f97b5ae426e14d2822917d3b69 ]

Create new config CONFIG_CXL_RAS and put all CXL RAS items behind the
config. The config will depend on CPER and PCIE AER to build. Move the
related VH RAS code from core/pci.c to core/ras.c.

Restricted CXL host (RCH) RAS functions will be moved in a future patch.

Cc: Robert Richter <rrichter@amd.com>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Co-developed-by: Terry Bowman <terry.bowman@amd.com>
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://patch.msgid.link/20260114182055.46029-8-terry.bowman@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

[ sashal: Reduced backport -- upstream 7ff8b1d60881c touches 8 file(s), this
  backport carries 6. Not backported here:
  drivers/cxl/cxl.h
  drivers/cxl/cxlpci.h
  drivers/cxl/Kconfig
  This note is generated from the file lists only; see the resolution record
  for the reasoning. ]

Stable-dep-of: 29458e62d082 ("cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cxl/core/Makefile  |   2 +
 drivers/cxl/core/core.h    |  12 ++
 drivers/cxl/core/pci.c     | 296 -------------------------------------
 drivers/cxl/core/ras.c     | 186 +++++++++++++++++++++++
 drivers/cxl/core/ras_rch.c | 121 +++++++++++++++
 tools/testing/cxl/Kbuild   |   2 +
 6 files changed, 323 insertions(+), 296 deletions(-)
 create mode 100644 drivers/cxl/core/ras.c
 create mode 100644 drivers/cxl/core/ras_rch.c

diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index 9259bcc6773c8..c673775cd1917 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -14,5 +14,7 @@ cxl_core-y += pci.o
 cxl_core-y += hdm.o
 cxl_core-y += pmu.o
 cxl_core-y += cdat.o
+cxl_core-y += ras.o
+cxl_core-$(CONFIG_PCIEAER_CXL) += ras_rch.o
 cxl_core-$(CONFIG_TRACING) += trace.o
 cxl_core-$(CONFIG_CXL_REGION) += region.o
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 0c62b4069ba00..efe567c679a20 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -110,4 +110,16 @@ bool cxl_need_node_perf_attrs_update(int nid);
 int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
 					struct access_coordinate *c);
 
+struct cxl_dev_state;
+bool cxl_handle_ras(struct cxl_dev_state *cxlds, void __iomem *ras_base);
+void cxl_handle_cor_ras(struct cxl_dev_state *cxlds, void __iomem *ras_base);
+
+#ifdef CONFIG_PCIEAER_CXL
+void cxl_dport_map_rch_aer(struct cxl_dport *dport);
+void cxl_disable_rch_root_ints(struct cxl_dport *dport);
+void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds);
+#else
+static inline void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) { }
+#endif
+
 #endif /* __CXL_CORE_H__ */
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 42fc18878b0d6..caecc07665057 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -650,302 +650,6 @@ void read_cdat_data(struct cxl_port *port)
 }
 EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
 
-static void cxl_handle_cor_ras(struct cxl_dev_state *cxlds,
-			       void __iomem *ras_base)
-{
-	void __iomem *addr;
-	u32 status;
-
-	if (!ras_base)
-		return;
-
-	addr = ras_base + CXL_RAS_CORRECTABLE_STATUS_OFFSET;
-	status = readl(addr);
-	if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) {
-		writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr);
-		trace_cxl_aer_correctable_error(cxlds->cxlmd, status);
-	}
-}
-
-/* CXL spec rev3.0 8.2.4.16.1 */
-static void header_log_copy(void __iomem *ras_base, u32 *log)
-{
-	void __iomem *addr;
-	u32 *log_addr;
-	int i, log_u32_size = CXL_HEADERLOG_SIZE / sizeof(u32);
-
-	addr = ras_base + CXL_RAS_HEADER_LOG_OFFSET;
-	log_addr = log;
-
-	for (i = 0; i < log_u32_size; i++) {
-		*log_addr = readl(addr);
-		log_addr++;
-		addr += sizeof(u32);
-	}
-}
-
-/*
- * Log the state of the RAS status registers and prepare them to log the
- * next error status. Return 1 if reset needed.
- */
-static bool cxl_handle_ras(struct cxl_dev_state *cxlds,
-			   void __iomem *ras_base)
-{
-	u32 hl[CXL_HEADERLOG_SIZE_U32];
-	void __iomem *addr;
-	u32 status;
-	u32 fe;
-
-	if (!ras_base)
-		return false;
-
-	addr = ras_base + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET;
-	status = readl(addr);
-	if (!(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK))
-		return false;
-
-	/* If multiple errors, log header points to first error from ctrl reg */
-	if (hweight32(status) > 1) {
-		void __iomem *rcc_addr =
-			ras_base + CXL_RAS_CAP_CONTROL_OFFSET;
-
-		fe = BIT(FIELD_GET(CXL_RAS_CAP_CONTROL_FE_MASK,
-				   readl(rcc_addr)));
-	} else {
-		fe = status;
-	}
-
-	header_log_copy(ras_base, hl);
-	trace_cxl_aer_uncorrectable_error(cxlds->cxlmd, status, fe, hl);
-	writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr);
-
-	return true;
-}
-
-#ifdef CONFIG_PCIEAER_CXL
-
-static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
-{
-	resource_size_t aer_phys;
-	struct device *host;
-	u16 aer_cap;
-
-	aer_cap = cxl_rcrb_to_aer(dport->dport_dev, dport->rcrb.base);
-	if (aer_cap) {
-		host = dport->reg_map.host;
-		aer_phys = aer_cap + dport->rcrb.base;
-		dport->regs.dport_aer = devm_cxl_iomap_block(host, aer_phys,
-						sizeof(struct aer_capability_regs));
-	}
-}
-
-static void cxl_dport_map_ras(struct cxl_dport *dport)
-{
-	struct cxl_register_map *map = &dport->reg_map;
-	struct device *dev = dport->dport_dev;
-
-	if (!map->component_map.ras.valid)
-		dev_dbg(dev, "RAS registers not found\n");
-	else if (cxl_map_component_regs(map, &dport->regs.component,
-					BIT(CXL_CM_CAP_CAP_ID_RAS)))
-		dev_dbg(dev, "Failed to map RAS capability.\n");
-}
-
-static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
-{
-	void __iomem *aer_base = dport->regs.dport_aer;
-	u32 aer_cmd_mask, aer_cmd;
-
-	if (!aer_base)
-		return;
-
-	/*
-	 * Disable RCH root port command interrupts.
-	 * CXL 3.0 12.2.1.1 - RCH Downstream Port-detected Errors
-	 *
-	 * This sequence may not be necessary. CXL spec states disabling
-	 * the root cmd register's interrupts is required. But, PCI spec
-	 * shows these are disabled by default on reset.
-	 */
-	aer_cmd_mask = (PCI_ERR_ROOT_CMD_COR_EN |
-			PCI_ERR_ROOT_CMD_NONFATAL_EN |
-			PCI_ERR_ROOT_CMD_FATAL_EN);
-	aer_cmd = readl(aer_base + PCI_ERR_ROOT_COMMAND);
-	aer_cmd &= ~aer_cmd_mask;
-	writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND);
-}
-
-/**
- * cxl_dport_init_ras_reporting - Setup CXL RAS report on this dport
- * @dport: the cxl_dport that needs to be initialized
- * @host: host device for devm operations
- */
-void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
-{
-	dport->reg_map.host = host;
-	cxl_dport_map_ras(dport);
-
-	if (dport->rch) {
-		struct pci_host_bridge *host_bridge = to_pci_host_bridge(dport->dport_dev);
-
-		if (!host_bridge->native_aer)
-			return;
-
-		cxl_dport_map_rch_aer(dport);
-		cxl_disable_rch_root_ints(dport);
-	}
-}
-EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, CXL);
-
-/*
- * Copy the AER capability registers using 32 bit read accesses.
- * This is necessary because RCRB AER capability is MMIO mapped. Clear the
- * status after copying.
- *
- * @aer_base: base address of AER capability block in RCRB
- * @aer_regs: destination for copying AER capability
- */
-static bool cxl_rch_get_aer_info(void __iomem *aer_base,
-				 struct aer_capability_regs *aer_regs)
-{
-	int read_cnt = sizeof(struct aer_capability_regs) / sizeof(u32);
-	u32 *aer_regs_buf = (u32 *)aer_regs;
-	int n;
-
-	if (!aer_base)
-		return false;
-
-	/* Use readl() to guarantee 32-bit accesses */
-	for (n = 0; n < read_cnt; n++)
-		aer_regs_buf[n] = readl(aer_base + n * sizeof(u32));
-
-	writel(aer_regs->uncor_status, aer_base + PCI_ERR_UNCOR_STATUS);
-	writel(aer_regs->cor_status, aer_base + PCI_ERR_COR_STATUS);
-
-	return true;
-}
-
-/* Get AER severity. Return false if there is no error. */
-static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
-				     int *severity)
-{
-	if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
-		if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
-			*severity = AER_FATAL;
-		else
-			*severity = AER_NONFATAL;
-		return true;
-	}
-
-	if (aer_regs->cor_status & ~aer_regs->cor_mask) {
-		*severity = AER_CORRECTABLE;
-		return true;
-	}
-
-	return false;
-}
-
-static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
-{
-	struct pci_dev *pdev = to_pci_dev(cxlds->dev);
-	struct aer_capability_regs aer_regs;
-	struct cxl_dport *dport;
-	int severity;
-
-	struct cxl_port *port __free(put_cxl_port) =
-		cxl_pci_find_port(pdev, &dport);
-	if (!port)
-		return;
-
-	if (!cxl_rch_get_aer_info(dport->regs.dport_aer, &aer_regs))
-		return;
-
-	if (!cxl_rch_get_aer_severity(&aer_regs, &severity))
-		return;
-
-	pci_print_aer(pdev, severity, &aer_regs);
-
-	if (severity == AER_CORRECTABLE)
-		cxl_handle_cor_ras(cxlds, dport->regs.ras);
-	else
-		cxl_handle_ras(cxlds, dport->regs.ras);
-}
-
-#else
-static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) { }
-#endif
-
-void cxl_cor_error_detected(struct pci_dev *pdev)
-{
-	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
-	struct device *dev = &cxlds->cxlmd->dev;
-
-	scoped_guard(device, dev) {
-		if (!dev->driver) {
-			dev_warn(&pdev->dev,
-				 "%s: memdev disabled, abort error handling\n",
-				 dev_name(dev));
-			return;
-		}
-
-		if (cxlds->rcd)
-			cxl_handle_rdport_errors(cxlds);
-
-		cxl_handle_cor_ras(cxlds, cxlds->regs.ras);
-	}
-}
-EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
-
-pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
-				    pci_channel_state_t state)
-{
-	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
-	struct cxl_memdev *cxlmd = cxlds->cxlmd;
-	struct device *dev = &cxlmd->dev;
-	bool ue;
-
-	scoped_guard(device, dev) {
-		if (!dev->driver) {
-			dev_warn(&pdev->dev,
-				 "%s: memdev disabled, abort error handling\n",
-				 dev_name(dev));
-			return PCI_ERS_RESULT_DISCONNECT;
-		}
-
-		if (cxlds->rcd)
-			cxl_handle_rdport_errors(cxlds);
-		/*
-		 * A frozen channel indicates an impending reset which is fatal to
-		 * CXL.mem operation, and will likely crash the system. On the off
-		 * chance the situation is recoverable dump the status of the RAS
-		 * capability registers and bounce the active state of the memdev.
-		 */
-		ue = cxl_handle_ras(cxlds, cxlds->regs.ras);
-	}
-
-
-	switch (state) {
-	case pci_channel_io_normal:
-		if (ue) {
-			device_release_driver(dev);
-			return PCI_ERS_RESULT_NEED_RESET;
-		}
-		return PCI_ERS_RESULT_CAN_RECOVER;
-	case pci_channel_io_frozen:
-		dev_warn(&pdev->dev,
-			 "%s: frozen state error detected, disable CXL.mem\n",
-			 dev_name(dev));
-		device_release_driver(dev);
-		return PCI_ERS_RESULT_NEED_RESET;
-	case pci_channel_io_perm_failure:
-		dev_warn(&pdev->dev,
-			 "failure state error detected, request disconnect\n");
-		return PCI_ERS_RESULT_DISCONNECT;
-	}
-	return PCI_ERS_RESULT_NEED_RESET;
-}
-EXPORT_SYMBOL_NS_GPL(cxl_error_detected, CXL);
-
 static int cxl_flit_size(struct pci_dev *pdev)
 {
 	if (cxl_pci_flit_256(pdev))
diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
new file mode 100644
index 0000000000000..6256b145a517f
--- /dev/null
+++ b/drivers/cxl/core/ras.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
+
+#include <linux/aer.h>
+#include <cxlmem.h>
+#include <cxlpci.h>
+#include "core.h"
+#include "trace.h"
+
+void cxl_handle_cor_ras(struct cxl_dev_state *cxlds, void __iomem *ras_base)
+{
+	void __iomem *addr;
+	u32 status;
+
+	if (!ras_base)
+		return;
+
+	addr = ras_base + CXL_RAS_CORRECTABLE_STATUS_OFFSET;
+	status = readl(addr);
+	if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) {
+		writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr);
+		trace_cxl_aer_correctable_error(cxlds->cxlmd, status);
+	}
+}
+
+/* CXL spec rev3.0 8.2.4.16.1 */
+static void header_log_copy(void __iomem *ras_base, u32 *log)
+{
+	void __iomem *addr;
+	u32 *log_addr;
+	int i, log_u32_size = CXL_HEADERLOG_SIZE / sizeof(u32);
+
+	addr = ras_base + CXL_RAS_HEADER_LOG_OFFSET;
+	log_addr = log;
+
+	for (i = 0; i < log_u32_size; i++) {
+		*log_addr = readl(addr);
+		log_addr++;
+		addr += sizeof(u32);
+	}
+}
+
+/*
+ * Log the state of the RAS status registers and prepare them to log the
+ * next error status. Return 1 if reset needed.
+ */
+bool cxl_handle_ras(struct cxl_dev_state *cxlds, void __iomem *ras_base)
+{
+	u32 hl[CXL_HEADERLOG_SIZE_U32];
+	void __iomem *addr;
+	u32 status;
+	u32 fe;
+
+	if (!ras_base)
+		return false;
+
+	addr = ras_base + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET;
+	status = readl(addr);
+	if (!(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK))
+		return false;
+
+	/* If multiple errors, log header points to first error from ctrl reg */
+	if (hweight32(status) > 1) {
+		void __iomem *rcc_addr =
+			ras_base + CXL_RAS_CAP_CONTROL_OFFSET;
+
+		fe = BIT(FIELD_GET(CXL_RAS_CAP_CONTROL_FE_MASK,
+				   readl(rcc_addr)));
+	} else {
+		fe = status;
+	}
+
+	header_log_copy(ras_base, hl);
+	trace_cxl_aer_uncorrectable_error(cxlds->cxlmd, status, fe, hl);
+	writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr);
+
+	return true;
+}
+
+#ifdef CONFIG_PCIEAER_CXL
+static void cxl_dport_map_ras(struct cxl_dport *dport)
+{
+	struct cxl_register_map *map = &dport->reg_map;
+	struct device *dev = dport->dport_dev;
+
+	if (!map->component_map.ras.valid)
+		dev_dbg(dev, "RAS registers not found\n");
+	else if (cxl_map_component_regs(map, &dport->regs.component,
+					BIT(CXL_CM_CAP_CAP_ID_RAS)))
+		dev_dbg(dev, "Failed to map RAS capability.\n");
+}
+
+/**
+ * cxl_dport_init_ras_reporting - Setup CXL RAS report on this dport
+ * @dport: the cxl_dport that needs to be initialized
+ * @host: host device for devm operations
+ */
+void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
+{
+	dport->reg_map.host = host;
+	cxl_dport_map_ras(dport);
+
+	if (dport->rch) {
+		struct pci_host_bridge *host_bridge =
+			to_pci_host_bridge(dport->dport_dev);
+
+		if (!host_bridge->native_aer)
+			return;
+
+		cxl_dport_map_rch_aer(dport);
+		cxl_disable_rch_root_ints(dport);
+	}
+}
+EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, CXL);
+#endif
+
+void cxl_cor_error_detected(struct pci_dev *pdev)
+{
+	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
+	struct device *dev = &cxlds->cxlmd->dev;
+
+	scoped_guard(device, dev) {
+		if (!dev->driver) {
+			dev_warn(&pdev->dev,
+				 "%s: memdev disabled, abort error handling\n",
+				 dev_name(dev));
+			return;
+		}
+
+		if (cxlds->rcd)
+			cxl_handle_rdport_errors(cxlds);
+
+		cxl_handle_cor_ras(cxlds, cxlds->regs.ras);
+	}
+}
+EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
+
+pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
+				    pci_channel_state_t state)
+{
+	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
+	struct cxl_memdev *cxlmd = cxlds->cxlmd;
+	struct device *dev = &cxlmd->dev;
+	bool ue;
+
+	scoped_guard(device, dev) {
+		if (!dev->driver) {
+			dev_warn(&pdev->dev,
+				 "%s: memdev disabled, abort error handling\n",
+				 dev_name(dev));
+			return PCI_ERS_RESULT_DISCONNECT;
+		}
+
+		if (cxlds->rcd)
+			cxl_handle_rdport_errors(cxlds);
+		/*
+		 * A frozen channel indicates an impending reset which is fatal to
+		 * CXL.mem operation, and will likely crash the system. On the off
+		 * chance the situation is recoverable dump the status of the RAS
+		 * capability registers and bounce the active state of the memdev.
+		 */
+		ue = cxl_handle_ras(cxlds, cxlds->regs.ras);
+	}
+
+
+	switch (state) {
+	case pci_channel_io_normal:
+		if (ue) {
+			device_release_driver(dev);
+			return PCI_ERS_RESULT_NEED_RESET;
+		}
+		return PCI_ERS_RESULT_CAN_RECOVER;
+	case pci_channel_io_frozen:
+		dev_warn(&pdev->dev,
+			 "%s: frozen state error detected, disable CXL.mem\n",
+			 dev_name(dev));
+		device_release_driver(dev);
+		return PCI_ERS_RESULT_NEED_RESET;
+	case pci_channel_io_perm_failure:
+		dev_warn(&pdev->dev,
+			 "failure state error detected, request disconnect\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_error_detected, CXL);
diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
new file mode 100644
index 0000000000000..ed58afd18ecc9
--- /dev/null
+++ b/drivers/cxl/core/ras_rch.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2025 AMD Corporation. All rights reserved. */
+
+#include <linux/types.h>
+#include <linux/aer.h>
+#include "cxl.h"
+#include "core.h"
+#include "cxlmem.h"
+
+void cxl_dport_map_rch_aer(struct cxl_dport *dport)
+{
+	resource_size_t aer_phys;
+	struct device *host;
+	u16 aer_cap;
+
+	aer_cap = cxl_rcrb_to_aer(dport->dport_dev, dport->rcrb.base);
+	if (aer_cap) {
+		host = dport->reg_map.host;
+		aer_phys = aer_cap + dport->rcrb.base;
+		dport->regs.dport_aer =
+			devm_cxl_iomap_block(host, aer_phys,
+					     sizeof(struct aer_capability_regs));
+	}
+}
+
+void cxl_disable_rch_root_ints(struct cxl_dport *dport)
+{
+	void __iomem *aer_base = dport->regs.dport_aer;
+	u32 aer_cmd_mask, aer_cmd;
+
+	if (!aer_base)
+		return;
+
+	/*
+	 * Disable RCH root port command interrupts.
+	 * CXL 3.0 12.2.1.1 - RCH Downstream Port-detected Errors
+	 *
+	 * This sequence may not be necessary. CXL spec states disabling
+	 * the root cmd register's interrupts is required. But, PCI spec
+	 * shows these are disabled by default on reset.
+	 */
+	aer_cmd_mask = (PCI_ERR_ROOT_CMD_COR_EN |
+			PCI_ERR_ROOT_CMD_NONFATAL_EN |
+			PCI_ERR_ROOT_CMD_FATAL_EN);
+	aer_cmd = readl(aer_base + PCI_ERR_ROOT_COMMAND);
+	aer_cmd &= ~aer_cmd_mask;
+	writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND);
+}
+
+/*
+ * Copy the AER capability registers using 32 bit read accesses.
+ * This is necessary because RCRB AER capability is MMIO mapped. Clear the
+ * status after copying.
+ *
+ * @aer_base: base address of AER capability block in RCRB
+ * @aer_regs: destination for copying AER capability
+ */
+static bool cxl_rch_get_aer_info(void __iomem *aer_base,
+				 struct aer_capability_regs *aer_regs)
+{
+	int read_cnt = sizeof(struct aer_capability_regs) / sizeof(u32);
+	u32 *aer_regs_buf = (u32 *)aer_regs;
+	int n;
+
+	if (!aer_base)
+		return false;
+
+	/* Use readl() to guarantee 32-bit accesses */
+	for (n = 0; n < read_cnt; n++)
+		aer_regs_buf[n] = readl(aer_base + n * sizeof(u32));
+
+	writel(aer_regs->uncor_status, aer_base + PCI_ERR_UNCOR_STATUS);
+	writel(aer_regs->cor_status, aer_base + PCI_ERR_COR_STATUS);
+
+	return true;
+}
+
+/* Get AER severity. Return false if there is no error. */
+static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
+				     int *severity)
+{
+	if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
+		if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
+			*severity = AER_FATAL;
+		else
+			*severity = AER_NONFATAL;
+		return true;
+	}
+
+	if (aer_regs->cor_status & ~aer_regs->cor_mask) {
+		*severity = AER_CORRECTABLE;
+		return true;
+	}
+
+	return false;
+}
+
+void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
+{
+	struct pci_dev *pdev = to_pci_dev(cxlds->dev);
+	struct aer_capability_regs aer_regs;
+	struct cxl_dport *dport;
+	int severity;
+
+	struct cxl_port *port __free(put_cxl_port) =
+		cxl_pci_find_port(pdev, &dport);
+	if (!port)
+		return;
+
+	if (!cxl_rch_get_aer_info(dport->regs.dport_aer, &aer_regs))
+		return;
+
+	if (!cxl_rch_get_aer_severity(&aer_regs, &severity))
+		return;
+
+	pci_print_aer(pdev, severity, &aer_regs);
+	if (severity == AER_CORRECTABLE)
+		cxl_handle_cor_ras(cxlds, dport->regs.ras);
+	else
+		cxl_handle_ras(cxlds, dport->regs.ras);
+}
diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index b1256fee3567f..773e56e3aa1d4 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -61,6 +61,8 @@ cxl_core-y += $(CXL_CORE_SRC)/pci.o
 cxl_core-y += $(CXL_CORE_SRC)/hdm.o
 cxl_core-y += $(CXL_CORE_SRC)/pmu.o
 cxl_core-y += $(CXL_CORE_SRC)/cdat.o
+cxl_core-y += $(CXL_CORE_SRC)/ras.o
+cxl_core-$(CONFIG_PCIEAER_CXL) += $(CXL_CORE_SRC)/ras_rch.o
 cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
 cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
 cxl_core-y += config_check.o
-- 
2.53.0

[PATCH 6.12.y 4/4] cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read

[Sasha Levin]

From: Terry Bowman <terry.bowman@amd.com>

[ Upstream commit 29458e62d0829cbc99435f3e44fd560f9bbf1da7 ]

cxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from
the RCRB MMIO block using a readl() loop bounded by sizeof(struct
aer_capability_regs). This struct is a software layout and its embedded
struct pcie_tlp_log is larger than the on-wire AER capability. As a
result the loop reads past the mapped AER register block.

The over-read also populates the software-only tail fields including
header_log.header_len. An out-of-range header_len passed to
pcie_print_tlp_log() can then loop past the header log buffer and cause
a second out-of-bounds read.

The read was correct when introduced, but struct pcie_tlp_log has since
grown (Header Log and TLP Prefix Log sizes, header_len and flit fields),
so sizeof(struct aer_capability_regs) no longer matches the physical AER
capability.

Bound the read to the physical AER registers, header through the 16 byte
Header Log. Zero the destination first so the software-only fields are
deterministic.

Fixes: 6ac07883dbb5 ("cxl/pci: Add RCH downstream port error logging")
Reported-by: Sashiko <sashiko@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20260803221810.3685703-2-terry.bowman@amd.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cxl/core/ras_rch.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
index ed58afd18ecc9..5170cebf6637b 100644
--- a/drivers/cxl/core/ras_rch.c
+++ b/drivers/cxl/core/ras_rch.c
@@ -58,13 +58,28 @@ void cxl_disable_rch_root_ints(struct cxl_dport *dport)
 static bool cxl_rch_get_aer_info(void __iomem *aer_base,
 				 struct aer_capability_regs *aer_regs)
 {
-	int read_cnt = sizeof(struct aer_capability_regs) / sizeof(u32);
+	/*
+	 * Bound the copy to the physically-defined AER registers (header
+	 * through the 16-byte Header Log). struct aer_capability_regs is a
+	 * software layout whose embedded struct pcie_tlp_log is larger than
+	 * the on-wire AER capability; copying sizeof(*aer_regs) would
+	 * over-read the RCRB-mapped MMIO block.
+	 */
+	int read_cnt = (PCI_ERR_HEADER_LOG + 16) / sizeof(u32);
 	u32 *aer_regs_buf = (u32 *)aer_regs;
 	int n;
 
 	if (!aer_base)
 		return false;
 
+	/*
+	 * Zero the destination so the software-only tail fields
+	 * (e.g. header_log.header_len) are deterministic rather than
+	 * left as uninitialized stack, which could drive a bogus loop
+	 * length in pcie_print_tlp_log().
+	 */
+	memset(aer_regs, 0, sizeof(*aer_regs));
+
 	/* Use readl() to guarantee 32-bit accesses */
 	for (n = 0; n < read_cnt; n++)
 		aer_regs_buf[n] = readl(aer_base + n * sizeof(u32));
-- 
2.53.0